Manufacture of cellulose-acetate artificial silk



so u at" a U U i Patented Aug. 25, 1925. UNITED STATES PATENT OFFICE.

HARRY S. MOB/K, F BRODKLINE, AND CHARLES E QQFFINIJR, OF WATER'IOWN,MASSACHTISE'I'TS, ASSIGNORS, BY MESNE ASSIGNMENTS, TO LUSTR-ON COMPANY,INC., OF BO STON, MASSACHUSETTS, A CORPORATION OF MASSAGI-IU$ETTS. S i1' 4 x MANUFACTURE OF GELLULOSE-ACETA'IE ARTIFICIAL SILK.

No Drawing. Application filed March 22, 1923. Serial No. 626,872.

To all whom 2'25 may comer-n:

Be it known that We (1) HARRY S. Moan, and (2) CHARLES F. dOFlIN, J12,citizens of the United States, residing at (1) Brookline, (2) Watertown,in the counties of (1) Norfolk, (2) Middlesex, and State of (1) and (2)Massachusetts, have invented certain new and useful Improvements in theMannfacture of Cellulose-Acetate Artificial Silk, of which the followingis a specification.

lhis invention relates specifically to improvements in the manufactureof cellulose acetate artificial silk as described in United StatesPatent No. 1,107,222, patented August 11, 1914:, to Harry S. Mork.

The said patentdescribes a process of making cellulose acetateartificial silk com.- prising dissolving the celluloseacetate in amixture of tetrachlorethaiie and an alcohol, and squirting the resultingsolution through fine orifices into a pggg ulgting gr bath composed ofone 6i inore aliphatic liydiihharbons, preferably petroleiunhydrocarbons, or a mixture of aliphatic hydrocarbons andtetrachloretlw-ne.

e have :tound that better coagulation can be secured, and consequentlymore uniform spinning conditions can be maintained, if there isincorporated in the original cellulose acetate solution a limitedproportion of an aliphatic hydrocarbon or mixtures of aliphatichydrocarbons. The ellect of such addition is to bring the spinningsolution considerably nearer to its coagulating point, and thereby toimprove the coagulation in the second bath. The aliq'hatic hydrocarbonsto be added may be the same as those used in the coagulating bath, butas this latter usually comprises a mixture of various hydrocarbonsboiling over aconsiderable temperature range, We regard it aspreferable, though not essential, to add tothe original solutionhydrocarbons correspond ing to the loner boiling constituents of thehydrocarbon mixture used in the coagulating bath. These lower-boilinghydrocarbons will dry out of the silk more rapidly. We do not howeverwish to restrict ourselves to the use of a hydrocarbon identical with acomponent of the coagulating bath, or a mixture of hydrocarbonscorresponding to the mixture employed in the coagulating bath.

When the coagulation bath becomes heavilychargednvith..telilflthlorethan h'stilldltai oone1:the..,.t and thedistillation may be conducted so that the tetrachloret-hane distilledoil will contain some hydrocarbons. Such a distillate can be used toprovide all or part of the totrachlo-rethane and hydrocarbon necessaryfor the preparation of the spinning solution.

No definite percentage can be prescribed ance with our invention, itbeing understoodthat the invention is not limited to the particularmaterials or proportions recited therein by Way of illustration:

306 grams of fibrous cellulose acetate prepared m accordance with theUnited States Patent 854,374, patented May 21, 1907, to Harry S. Mork,are dissolved in a mixture ol 1120 e. c. of tetrachlorethane, 420 c. c.of denatured alcohol and 160 c. c. of 150 fire test kerosene. Thesolution'is thoroughly agitated, then filtered and squirted underpressure througha suitable spinneret into a coagulating bath composed of9 parts by volume of kerosene and 1 part by volume of tetrachlorethane.

Another method of preparing a spinning solution is as follows:

306 grams of cellulose acetate are dissolved m a mixture of 1280 c. c.of tetrachlorethane distillate and 120 c. c. of denatured alcohol. lhedistillate may contain 87 72; of tetrachlorethane and 12 kesosene byvolume.

It is not essential that the hydrocarbon be present in the solventmixture when the cellulose acetate is dissolved because the celluloseacetate may first be dissolved in a mixture of commercially puretetrachlorethane and a suitable alcohol and the hydrocarbon besubsequently mixed into the solution.

' tain.

To the solutions as above described may be further added other solventsand nonsolvents of the cellulose acetate such as chloroform, acetone,benzol, 'toluol, xylol, ethyl-methyl ketone, ethyl acetate, and carbontetrachloride, for the purpose. of altering the coagulation propertiesof the solu tion or the character of the artificial silk producedtherefrom. Similar results are obtained by the addition of aliphatichydrocarbons or mixtures thereof or mixtures of alipathie hydrocarbonswith other solvents and non-solvents of cellulose acetate to solutionsof cellulose acetate insolvents other than 'tetraohlorethane ortetrachlorcthane and alcohol hereinbefore described. Other solvents forthe cellulose acetate which may be used are for example chlorinatedhydrocarbons of lower boiling point than tetrachlorethane,dichlormetlmne, chloroform, dicl'ilorethane, trichloretlnme etc., eitheralone or in conjunction With alcohol.

We claim:

1. As a novel composition of matter, a coagulable solution comprisingcellulose acetate, tctrachlorethane, and an aliphatic hydrocarbon.

2. As a novel composition of matter, a

coagulable solution comprising cellulose acetate, tetrachlorethane, analiphatic hydrocarbon and an alcohol.

Process of making cellulose acetate artificial silk comprising preparinga solution of cellulose acetate in a solvent containing'tetrachlorethane and an aliphatic hydrocarbon, and coagulating saidsolution in a bath likewise containing an aliphatic hydrocarbon.

at. Process according to claim 3 in which the cellulose acetate solventcomprises tetrachlorcthane, an alcohol, and an aliphatic hyd rocarbon.

As a novel composition of matter, a coagulable solution comprisingcellulose acetate, a solvent therefor, and. an aliphatic hydrocarbon.

(3. Process of making cellulose acetate artificial sill: comprisingpreparing a solution comprising cellulose acetate, a. cellulose acetatesolvent and an aliphatic hydrocarhon, and coagulating said solution in abath comprising an aliphatic hydrocarbon.

In testimony whereof, We all'ix our signatures.

I-IARRY S. MORK. CHARLES F. COFFIN, JR.

